Effect of Plasma Treatment on Ice Plant Germination and Physicochemical Surface Using Dielectric Barrier Discharge

Atmospheric pressure plasma treatment on seeds has recently become a valuable technique to improve germination. This work treated Mesembryanthemum crystallinum (ice plant) seeds by the dielectric barrier discharge (DBD) atmospheric pressure plasma at room temperature. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) indicate that after plasma treatment, the N–H stretching vibration of proteins ( $\sim 3340$ cm $^{-1}$ ) is introduced into the seed surface, increasing the nitrogen content on the surface of the ice plant. Therefore, the seed germination rate increased significantly by 15.2%. However, prolonged plasma treatment reduces seed germination. Because the operating surrounding temperature increases with the treatment time, the wax on the surface of the seed is evaporated, resulting in a significant increase water uptake of seeds. Excess water uptake hinders oxygen diffusion to the embryo, affecting germination. A feasible mechanism and effects of plasma treatment on ice plants are proposed in this study. DBD plasma-treated ice plants significantly increase germination rates, showing excellent potential in the agricultural field.